[Halld-controls] PXI Time Stamps

[Brian Eng]

No, since we don't really care about the UTC <-> TIA offset it would just be updating the PXI to (hopefully) undo that offset that the PLC uses. So far Rockwell has said it is hard-coded and we can't modify it.

However, the PVs seem backwards to me (PXI is ~30 sec slower than the PLC, when it should be faster). See attached screenshots.

Are there any timestamps from the SOE on the last dump? On the FastDAQ ROOT program, where are the timestamps coming from? The IOC or the PXI? If it comes from the IOC then we don't need to do anything with the PXI.

I have no plans on doing anything with the PLC unless/until they have a firmware we can set that offset to 0.

----- Original Message -----
> From: "Hovanes Egiyan" <hovanes.egiyan at gmail.com>
> To: halld-controls at jlab.org
> Sent: Tuesday, September 4, 2018 9:47:23 AM
> Subject: Re: [Halld-controls] PXI Time Stamps

> Brian, are you going to change the firmware on a PLC module? I did not quite
> 
> 
> understand what is going to be upgraded and rebooted.
> 
> 
> Hovanes.
> 
> On 09/04/2018 09:42 AM, Beni Zihlmann wrote:
> 
> 
> I think yes we should do this.
> 
> On 09/04/2018 09:36 AM, Timothy Whitlatch wrote:
> 
> 
> 
> Hi Brian,
> 
> We will have time this week to reboot the PXI (Just not today).
> 
> Hovanes and Beni, do you think we should implement the fix this week?
> 
> 
> Tim Whitlatch
> Hall D Engineer
> Jefferson Lab
> 600 KELVIN DR STE 5
> Newport News, VA 23606-4468
> 757-269-5087
> 
> 
> From: "Brian Eng" <beng at jlab.org>
> To: "Hall D Controls" <halld-controls at jlab.org>
> Sent: Thursday, August 30, 2018 1:46:47 PM
> Subject: [Halld-controls] PXI Time Stamps
> 
> We recently discovered that the time used by the PLCs has a offset to it which
> causes them to use/provide an incorrect time.
> 
> It manifests itself in 2 ways:
> 1) If the CC server is the master the PLC will be 34 seconds fast
> 2) if the PLC is the master any devices on the same subnet will be 34 seconds
> fast
> 
> That 34 seconds is hard-coded in the PLC ethernet module and only changed by
> upgrading the firmware (but it still won't be user adjustable). It comes from
> the offset between UTC & TAI time when the module was purchased.
> 
> Currently we're operating in the second configuration.
> 
> There is an option to correct this offset with Linux based NI devices, but I
> haven't yet tested it with the other OSes (namely the PXI which uses Phar Lap).
> 
> Unfortunately even if I can remove this offset it will require rebooting the
> PXI, so my question is should I try pursuing fixing this or is knowing that
> there is a fixed & constant offset good enough for now?
> 
> 
> 
> 
> P.S. This isn't like the earlier time problems we had where the time would
> slowly wander off, this is a fixed value with only the error of PTP coming into
> play which should be at the sub-ms level.ls
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